Subsea connection apparatus for a surface blowout preventer stack

Abstract

A subsea connection apparatus to allow connecting a surface blowout preventer stack and riser to a subsea wellhead is disclosed. The subsea connection apparatus uses a single cavity blowout preventer with a set of shearing blind rams. Hydraulically actuated wellhead connectors are secured to the top and bottom of the blowout preventer to allow connection to a subsea wellhead below the subsea connection apparatus and a well head hub profile on the lower end of a riser above the apparatus. A control system can operate both of the hydraulically actuated connectors and the blowout preventer independently. A frangible bore protector is disposed in the bore of the blowout preventer to protect the shearing blind rams from pipe, tools, and fluids being passed through the blowout preventer and can be sheared by the shearing blind rams along with any drill pipe in the bore.

What is claimed is: 
     
       1. An apparatus configured to protect a bore of a blowout preventer configured to be coupled to well equipment including a bore therethrough for the passage of a component, comprising:
 an annular member configured to be placed in and protect the bore of the blowout preventer and comprising a bore sized substantially equal to the bore of the well equipment; 
 wherein the annular member is configured to allow unrestricted passage of the component through the annular member and the well equipment; and 
 wherein the annular member comprises a frangible material. 
 
     
     
       2. The apparatus of  claim 1 , wherein the bore of the blowout preventer is larger than the bore of the well equipment. 
     
     
       3. The apparatus of  claim 1 , wherein the frangible material of the annular member comprises clay. 
     
     
       4. The apparatus of  claim 1 , wherein the frangible material of the annular member comprises glass. 
     
     
       5. The apparatus of  claim 1 , wherein the frangible material of the annular member comprises concrete. 
     
     
       6. The apparatus of  claim 1 , wherein the component comprises production casing. 
     
     
       7. A subsea apparatus configured to connect to equipment subsea, the equipment including a bore therethrough for the passage of a component, the apparatus comprising:
 a subsea blowout preventer assembly comprising a bore therethrough; 
 an annular member located in the subsea blowout preventer assembly bore and comprising a bore sized substantially equal to the bore of the equipment; 
 wherein the annular member is configured to allow unrestricted passage of the component through the annular member and the equipment; and 
 wherein the annular member comprises a frangible material. 
 
     
     
       8. The apparatus of  claim 7 , wherein the subsea blowout preventer assembly bore is larger than the bore of the equipment. 
     
     
       9. The apparatus of  claim 7 , wherein an outer diameter of the annular member is substantially equal to an inner diameter of the blowout preventer assembly bore. 
     
     
       10. The apparatus of  claim 7 , wherein the frangible material of the annular member comprises clay. 
     
     
       11. The apparatus of  claim 7 , wherein the frangible material of the annular member comprises glass. 
     
     
       12. The apparatus of  claim 7 , wherein the frangible material of the annular member comprises concrete. 
     
     
       13. The apparatus of  claim 7 , further comprising:
 wherein the blowout preventer assembly comprises a ram blowout preventer; and 
 wherein the annular member is breakable by the ram blowout preventer. 
 
     
     
       14. The apparatus of  claim 7 , wherein the annular member is coaxial with the blowout preventer assembly bore. 
     
     
       15. The apparatus of  claim 7 , wherein the ram blowout preventer assembly comprises a shear ram. 
     
     
       16. The apparatus of  claim 7 , wherein the ram blowout preventer assembly comprises a blind ram. 
     
     
       17. The apparatus of  claim 7 , wherein the blowout preventer assembly comprises two ram blowout preventers. 
     
     
       18. The apparatus of  claim 7 , wherein the component comprises production casing.